Anomalous Spin Response in Non-centrosymmetric Compounds

We examine static spin susceptibilities chi(alpha beta)(q) of spin components S-alpha and S-beta in the non-centrosymmetric tetragonal system. The anomalous susceptibility, which vanish in centrosymmetric systems, remains showing a momentum dependence like chi(xx)(q) - chi(yy)(q) similar to q(x)(2) - q(y)(2) and chi(xy)(q) + chi(yx)(q) similar to q(x)q(y). A characteristic property of the non-centrosymmetric system is the non-vanishing anomalous susceptibility, whose momentum dependence is not invariant to some symmetry operations of the system. As the direct probe of the anomalous spin susceptibility, we propose a polarized neutron scattering experiment, especially, around an ordering wave vector.